CNS manifestations of cytomegalovirus infections: diagnosis and treatment

Distribution of ganciclovir in the porcine central nervous system

Ganciclovir is often used compassionately for encephalitis due to cytomegalovirus (CMV) and human herpes virus 6b (HHV-6b). Ganciclovir pharmacokinetic studies in the central nervous system (CNS) generally rely on single measurements in the cerebrospinal fluid (CSF) or homogenized brain tissue. Therefore the objective was to compare brain extracellular fluid (ECF) concentrations of ganciclovir with plasma and CSF concentrations in a porcine model, using microdialysis during a 24 h period. Six Danish landrace pigs (female, age 4 months, 31-37 kg) received two weight-adjusted intravenous doses of ganciclovir. Unbound ganciclovir concentrations were determined by microdialysis over 24 h in five compartments: CSF (lateral ventricle, cisterna magna, and lumbar) and brain ECF (cortical and subcortical). Data were compared with paired plasma samples. Ganciclovir concentrations >IC50 for CMV (1.6 µg/mL) were achieved in all compartments. Concentrations >IC90 for CMV (8.3 µg/mL) were only achieved in plasma and the lumbar CSF compartment. The concentration time curves indicated higher lumbar and cisternal CSF concentrations than ECF concentrations. The ECF compartments achieved greater maximum concentration (Cmax), area under the concentration time curve (AUC), and time >IC50 after the second dose, and an accumulation ratio (Rac) >1. The greater Cmax, AUC, time >IC50, and Rac >1 in the ECF compartments with repeated dosages suggest that therapeutic concentrations may be achieved during long-term treatment. A higher loading dose might be warranted to improve early viral inhibition.

Shared interactions of six neurotropic viruses with 38 human proteins: a computational and literature-based exploration of viral interactions and hijacking of human proteins in neuropsychiatric disorders

INTRODUCTION

Viral infections may disrupt the structural and functional integrity of the nervous system, leading to acute conditions such as encephalitis, and neuropsychiatric conditions as mood disorders, schizophrenia, and neurodegenerative diseases. Investigating viral interactions of human proteins may reveal mechanisms underlying these effects and offer insights for therapeutic interventions. This study explores molecular interactions of virus and human proteins that may be related to neuropsychiatric disorders.

METHODS

Herpes Simplex Virus-1 (HSV-1), Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Influenza A virus (IAV) (H1N1, H5N1), and Human Immunodeficiency Virus (HIV1&2) were selected as key viruses. Protein structures for each virus were accessed from the Protein Data Bank and analyzed using the HMI-Pred web server to detect interface mimicry between viral and human proteins. The PANTHER classification system was used to categorize viral-human protein interactions based on function and cellular localization.

RESULTS

Energetically favorable viral-human protein interactions were identified for HSV-1 (467), CMV (514), EBV (495), H1N1 (3331), H5N1 (3533), and HIV 1&2 (62425). Besides immune and apoptosis-related pathways, key neurodegenerative pathways, including those associated with Parkinson's and Huntington's diseases, were frequently interacted. A total of 38 human proteins, including calmodulin 2, Ras-related botulinum toxin substrate 1 (Rac1), PDGF-β, and vimentin, were found to interact with all six viruses.

CONCLUSION

The study indicates a substantial number of energetically favorable interactions between human proteins and selected viral proteins, underscoring the complexity and breadth of viral strategies to hijack host cellular mechanisms. Further in vivo and in vitro validation is required to understand the implications of these interactions.

Molecular diagnostics in cerebrospinal fluid for the diagnosis of central nervous system infections

SUMMARYCentral nervous system (CNS) infections can be caused by various pathogens, including bacteria, viruses, fungi, and parasites. Molecular diagnostic methods are pivotal for identifying the different causative pathogens of these infections in clinical settings. The efficacy and specificity of these methods can vary per pathogen involved, and in a substantial part of patients, no pathogen is identified in the cerebrospinal fluid (CSF). Over recent decades, various molecular methodologies have been developed and applied to patients with CNS infections. This review provides an overview of the accuracy of nucleic acid amplification methods in CSF for a diverse range of pathogens, examines the potential value of multiplex PCR panels, and explores the broad-range bacterial and fungal PCR/sequencing panels. In addition, it evaluates innovative molecular approaches to enhance the diagnosis of CNS infections.

Microbiomes detected by cerebrospinal fluid metagenomic next-generation sequencing among patients with and without HIV with suspected central nervous system infection

BACKGROUND

Opportunistic infections in the central nervous system (CNS) can be a serious threat to people living with HIV. Early aetiological diagnosis and targeted treatment are crucial but difficult. Metagenomic next-generation sequencing (mNGS) has significant advantages over traditional detection methods. However, differences in the cerebrospinal fluid (CSF) microbiome profiles of patients living with and without HIV with suspected CNS infections using mNGS and conventional testing methods have not yet been adequately evaluated.

METHODS

We conducted a retrospective cohort study in the first hospital of Changsha between January 2019 and June 2022 to investigate the microbiomes detected using mNGS of the CSF of patients living with and without HIV with suspected CNS infections. The pathogens causing CNS infections were concurrently identified using both mNGS and traditional detection methods. The spectrum of pathogens identified was compared between the two groups.

RESULTS

Overall, 173 patients (140 with and 33 without HIV) with suspected CNS infection were enrolled in our study. In total, 106 (75.7%) patients with and 16 (48.5%) patients without HIV tested positive with mNGS (p = 0.002). Among the enrolled patients, 71 (50.7%) with HIV and five (15.2%) without HIV tested positive for two or more pathogens (p < 0.001). Patients with HIV had significantly higher proportions of fungus (20.7% vs. 3.0%, p = 0.016) and DNA virus (59.3% vs. 21.2%, p < 0.001) than those without HIV. Epstein-Barr virus (33.6%) was the most commonly identified potential pathogen in the CSF of patients living with HIV using mNGS, followed by cytomegalovirus (20.7%) and torque teno virus (13.8%). The top three causative pathogens identified in patients without HIV were Streptococcus (18.2%), Epstein-Barr virus (12.1%), and Mycobacterium tuberculosis (9.1%). In total, 113 patients living with HIV were diagnosed as having CNS infections. The rate of pathogen detection in people living with HIV with a CNS infection was significantly higher with mNGS than with conventional methods (93.8% vs. 15.0%, p < 0.001).

CONCLUSION

CSF microbiome profiles differ between patients living with and without HIV with suspected CNS infection. mNGS is a powerful tool for the diagnosis of CNS infection among people living with HIV, especially in those with mixed infections.

Evaluation of Alinity m CMV assay performance for detecting CMV in plasma, cerebrospinal fluid, and bronchoalveolar lavage specimens

Accurate detection and quantification of cytomegalovirus (CMV) is crucial to preventing adverse outcomes in immunocompromised individuals. Current assays were developed for use with plasma specimens, but CMV may be present in bronchoalveolar lavage (BAL) fluid and cerebrospinal fluid (CSF). We evaluated the performance of the Abbott Alinity m CMV assay compared to the Abbott RealTime CMV assay for quantification of CMV in plasma, BAL, and CSF specimens. To evaluate clinical performance, 190 plasma, 78 BAL, and 20 CSF specimens were tested with the Alinity m assay and compared to the RealTime assay. The Alinity m CMV assay showed high precision (SD <0.01 to 0.13) for all 3 specimen types. Clincal plasma and BAL specimens with quantifiable CMV DNA demonstrated strong correlation to RealTime CMV assay results (r2 = 0.9779 for plasma, r2 = 0.9373 for BAL). The Alinity m CMV assay may be useful for quantification of CMV in plasma, BAL, and CSF specimens.

Viral meningoencephalitis in pediatric solid organ or hematopoietic cell transplant recipients: a diagnostic and therapeutic approach

Neurologic complications, both infectious and non-infectious, are frequent among hematopoietic cell transplant (HCT) and solid organ transplant (SOT) recipients. Up to 46% of HCT and 50% of SOT recipients experience a neurological complication, including cerebrovascular accidents, drug toxicities, as well as infections. Defects in innate, adaptive, and humoral immune function among transplant recipients predispose to opportunistic infections, including central nervous system (CNS) disease. CNS infections remain uncommon overall amongst HCT and SOT recipients, compromising approximately 1% of total cases among adult patients. Given the relatively lower number of pediatric transplant recipients, the incidence of CNS disease amongst in this population remains unknown. Although infections comprise a small percentage of the neurological complications that occur post-transplant, the associated morbidity and mortality in an immunosuppressed state makes it imperative to promptly evaluate and aggressively treat a pediatric transplant patient with suspicion for viral meningoencephalitis. This manuscript guides the reader through a broad infectious and non-infectious diagnostic differential in a transplant recipient presenting with altered mentation and fever and thereafter, elaborates on diagnostics and management of viral meningoencephalitis. Hypothetical SOT and HCT patient cases have also been constructed to illustrate the diagnostic and management process in select viral etiologies. Given the unique risk for various opportunistic viral infections resulting in CNS disease among transplant recipients, the manuscript will provide a contemporary review of the epidemiology, risk factors, diagnosis, and management of viral meningoencephalitis in these patients.

Virus-Specific T-Cell Therapy for Viral Infections of the Central Nervous System: A Review

Opportunistic viral infections of the central nervous system represent a significant cause of morbidity and mortality among an increasing number of immunocompromised patients. Since antiviral treatments are usually poorly effective, the prognosis generally relies on the ability to achieve timely immune reconstitution. Hence, strategies aimed at reinvigorating antiviral immune activity have recently emerged. Among these, virus-specific T-cells are increasingly perceived as a principled and valuable tool to treat opportunistic viral infections. Here we briefly discuss how to develop and select virus-specific T-cells, then review their main indications in central nervous system infections, including progressive multifocal leukoencephalopathy, CMV infection, and adenovirus infection. We also discuss their potential interest in the treatment of progressive multiple sclerosis, or EBV-associated central nervous system inflammatory disease. We finish with the key future milestones of this promising treatment strategy.

Viral meningitis and encephalitis: an update

PURPOSE OF REVIEW

The most common infectious etiologies of meningitis and encephalitis are viruses. In this review, we will discuss current epidemiology, prevention, diagnosis, and treatment of the most common causes of viral meningitis and encephalitis worldwide.

RECENT FINDINGS

Viral meningitis and encephalitis are increasingly diagnosed as molecular diagnostic techniques and serologies have become more readily available worldwide but recent progress in novel antiviral therapies remains limited. Emerging and re-emerging viruses that have caused endemic or worldwide outbreaks or epidemics are arboviruses (e.g., West Nile virus, Japanese encephalitis, Tick borne encephalitis, Dengue, Zika, Toscana), enteroviruses (e.g., Enterovirus 71, Enterovirus D68), Parechoviruses, respiratory viruses [e.g., severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza, metapneumoviruses, measles, mumps], and herpes viruses [e.g., herpes simplex virus (HSV) type 1 (HSV-1), HSV-2, human herpes (HV) 6, varicella zoster virus (VZV)]. Future efforts should concentrate in increasing availability for those viruses with effective vaccination [e.g., Japanese encephalitis, Tick borne encephalitis, varicella zoster viruses, SARS-CoV-2, influenza], prompt initiation of those with encephalitis with treatable viruses (e.g., HSV-1, VZV), increasing the diagnostic yield by using novel techniques such as metagenomic sequencing and avoiding unnecessary antibiotics in those with viral meningitis or encephalitis.

SUMMARY

We review the current epidemiology, clinical presentation, diagnosis, and treatment of the common causative agents of viral meningitis and encephalitis worldwide.

Inhibition of Cytomegalovirus by Pentacta pygmaea Fucosylated Chondroitin Sulfate Depends on Its Molecular Weight

Many viruses attach to host cells by first interacting with cell surface proteoglycans containing heparan sulfate (HS) glycosaminoglycan chains and then by engaging with specific receptor, resulting in virus entry. In this project, HS–virus interactions were targeted by a new fucosylated chondroitin sulfate from the sea cucumber Pentacta pygmaea (PpFucCS) in order to block human cytomegalovirus (HCMV) entry into cells. Human foreskin fibroblasts were infected with HCMV in the presence of PpFucCS and its low molecular weight (LMW) fractions and the virus yield at five days post-infection was assessed. The virus attachment and entry into the cells were visualized by labeling the purified virus particles with a self-quenching fluorophore octadecyl rhodamine B (R18). The native PpFucCS exhibited potent inhibitory activity against HCMV specifically blocking virus entry into the cell and the inhibitory activities of the LMW PpFucCS derivatives were proportional to their chain lengths. PpFucCS and the derived oligosaccharides did not exhibit any significant cytotoxicity; moreover, they protected the infected cells from virus-induced lytic cell death. In conclusion, PpFucCS inhibits the entry of HCMV into cells and the high MW of this carbohydrate is a key structural element to achieve the maximal anti-viral effect. This new marine sulfated glycan can be developed into a potential prophylactic and therapeutic antiviral agent against HCMV infection.

Anti-cytomegalovirus preemptive therapy to prevent cytomegalovirus disease in HIV-infected patients: a systematic review

BACKGROUND

HIV patients are at higher risk of contracting and developing into an asymptomatic form of CMV infection. This review aimed to evaluate the efficacy and safety of preemptive therapy for preventing CMV disease in HIV patients.

METHODS

The electronic search was conducted in MEDLINE/PubMed and CENTRAL from inception until 9 September 2022. Studies were included if they assessed the efficacy or safety of anti-CMV preemptive therapy compared to placebo or no therapy. Risk of bias were assessed using the Cochrane Risk of Bias tool for randomized trials version 2 or the Cochrane Collaboration Risk of Bias in Non-randomized Studies of Interventions. The random-effects model was used to calculate effect sizes.

RESULTS

We identified six RCTs (2135 participants) and four observational studies (395 participants), with five RCTs were performed before highly active antiretroviral therapy (HAART) era. Preemptive therapy did not reduce the incidence of CMV disease (RR 0.84, 95% CI: 0.59-1.18), yet reduced the RR of all-cause mortality rate by 26% (RR 0.85, 95% CI: 0.74-0.97) with a low quality of evidence. The incidence of neutropenia as an adverse event increased significantly (RR 2.47, 95% CI: 1.12-5.45) with moderate quality of evidence.

CONCLUSIONS

With the advent of HAART, a limited number of studies have been performed to explore anti-CMV preemptive therapy due to the improved outcomes of HIV patients with CMV viremia. Therefore, optimal HAART should take precedence over anti-CMV preemptive therapy. The protocol for this review was registered in the Prospective Register of Systematic Reviews (CRD42020145765).

Family Herpesviridae and neuroinfections: current status and research in progress

This article addresses the relationship between human herpesviruses (HHVs) and neuroinfections. Alphaherpesviruses, betaherpesviruses and gammaherpesviruses are neurotropic viruses that establish latency and exhibit reactivation capacity. Encephalitis and meningitis are common in cases of HHV. The condition promoted by HHV infection is a purported trigger for certain neurodegenerative diseases. Ongoing studies have identified an association between HSV-1 and the occurrence of Alzheimer's disease, multiple sclerosis and infections by HHV-6 and Epstein-Barr virus. In this review, we highlight the importance of research investigating the role of herpesviruses in the pathogenesis of diseases that affect the nervous system and describe other studies in progress.

Are We Aware of the Neurological Manifestations of Cytomegalovirus Infection in Immunocompetent Individuals?

BACKGROUND

While cytomegalovirus (CMV) infection usually causes disease in immunosuppressed individuals, it mostly progresses as an asymptomatic infection in healthy adults. However, very rarely, immunocompetent individuals may also suffer from encephalitis and stroke.

METHODS

Nine patients who were admitted to the Neurology Clinic of Abant Izzet Baysal University Faculty of Medicine from 2016 to 2020 who had various neurological symptoms and were diagnosed with CMV infection were retrospectively analyzed. Symptoms, examination findings, laboratory results, radiologic imaging, and treatments were recorded and evaluated.

RESULTS

Although severe infections because of CMV generally occur in newborns and immunosuppressed adults, it is estimated that the disease is more common in immunocompetent adults than known. This may be associated with unrecognized risks, in part because of immune dysfunction or comorbidities such as renal failure or diabetes mellitus. Also, CMV replication in arterial endothelial cells can restrict blood flow, inducing an atherosclerotic environment and causing stroke. Diagnosis is based on clinical suspicion and serology. Ganciclovir is administered for treatment.

CONCLUSION

CMV infection should be considered in the differential diagnosis of patients presenting with neurological symptoms, even among immunocompetent individuals, because of the high possibility that patients can greatly benefit from antiviral treatment at the early stage.

Mycophenolate Mofetil-Induced Cytomegalovirus Colitis in a Patient With Polymyositis

As the rate of autoimmune conditions and cancers is increasing in the United States, a larger number of patients are being managed with immunosuppressive medications. Diarrhea is a common problem in immunocompromised patients. A feared complication of immunosuppression is infection with opportunistic pathogens. Cytomegalovirus is an opportunistic infection that can cause infection in a variety of different organ systems, including affecting the gastrointestinal system. Severe infection is most commonly seen as a complication of acquired immunodeficiency syndrome (AIDS), organ transplant, hematological malignancy, or cancer therapy. This case report describes a case of cytomegalovirus colitis in an immunosuppressed patient following mycophenolate mofetil (CellCept) therapy.

Atypical presentation and diagnosis of AIDS-related CMV encephalitis

We report a case of man in his 40s with a medical history of post-traumatic stress disorder who presented to the emergency department with altered mental status, ataxia, headache and dizziness a few hours after snorting amphetamines and mushrooms. Twenty-four hours after presentation, while no longer abusing amphetamines or mushrooms, he remained ataxic and dizzy. A CT scan of the head showed periventricular hypodensities. MRI of the brain revealed extensive confluent T2 hyperintense signal throughout the cerebral white matter, brainstem and cerebellar white matter. Given these findings and persistent ataxia, lumbar puncture was performed, and cerebrospinal fluid (CSF) meningoencephalitis panel was positive for cytomegalovirus (CMV), prompting a diagnosis of CMV encephalitis. Since CMV almost always occurs in the setting of immunocompromise, the patient was screened for HIV and found to be positive with a CD4 count of 22. He was treated with ganciclovir 5 mg/kg/dose intravenously every 12 hours, with resolution of all symptoms.

Human cytomegalovirus: a survey of end-organ diseases and diagnostic challenges in solid organ transplant recipients

PURPOSE OF REVIEW

Human cytomegalovirus (CMV) infection is one of the most important infectious complications in solid organ transplant (SOT) recipients, leading to significant morbidity and mortality. Therefore, early detection and prompt treatment are imperative to improve transplant outcomes. This article highlights the clinical characteristics of the most common CMV end-organ diseases in SOT recipients and their diagnostic modalities and challenges.

RECENT FINDINGS

CMV can cause a variety of end-organ diseases in SOT recipients. Although CMV nucleic acid amplification by polymerase chain reaction (PCR) is frequently employed to detect CMV reactivation or infection, its predictive value for various CMV end-organ diseases remains uncertain. Given the limitation of PCR or other noninvasive tests, confirmation of CMV end-organ disease may require tissue biopsy, which may not be feasible or available, or may cause untoward complications.

SUMMARY

The utility of PCR to diagnose CMV end-organ disease is limited. As CMV can infect any organ system(s), clinicians caring for SOT recipients need to maintain vigilance for any signs and symptoms of end-organ disease to allow early recognition and prompt treatment. Invasive procedures might be needed to confirm the diagnosis and minimize the empirical use of antiviral therapy that may have substantial drug toxicities.

Approach to Neurologic Complications in the Immunocompromised Patient

Neurologic complications are common in immunocompromised patients, including those with advanced human immunodeficiency virus, transplant recipients, and patients on immunomodulatory medications. In addition to the standard differential diagnosis, specific pathogens and other conditions unique to the immunocompromised state should be considered in the evaluation of neurologic complaints in this patient population. A thorough understanding of these considerations is critical to the inpatient neurologist in contemporary practice, as increasing numbers of patients are exposed to immunomodulatory therapies. In this review, we provide a chief complaint-based approach to the clinical presentations and diagnosis of both infectious and noninfectious complications particular to immunocompromised patients.

Infections of the Spine and Spinal Cord

PURPOSE OF REVIEW

Infections of the spine and spinal cord are associated with a high risk of morbidity and mortality and, therefore, require prompt clinical recognition, efficient diagnostic evaluation, and interdisciplinary treatment. This article reviews the pathophysiology, epidemiology, clinical manifestations, diagnosis, and treatment of infections of the spine and spinal cord to help practicing clinicians recognize, evaluate, and manage patients with such infections.

RECENT FINDINGS

Aging of the population, increasing use of immunosuppressive medications, and other factors have contributed to increasing rates of spinal infections. Although the most common agents responsible for spinal infections remain bacteria and viruses, fungal infections occur in individuals who are immunocompromised, and parasitic infections are common in endemic regions, but patterns are in evolution with migration and climate change. Recent outbreaks of acute flaccid myelitis in children have been associated with enteroviruses A71 and D68.

SUMMARY

Infections of the spine and spinal cord can be challenging to diagnose, requiring a thorough history and neurologic examination, laboratory studies of serum and CSF, neuroimaging (particularly MRI), and, in some instances, biopsy, to establish a diagnosis and treatment regimen. Interdisciplinary management including collaboration with experts in internal medicine, infectious disease, and neurosurgery is important to improve clinical outcomes.

Distinguishing cytomegalovirus meningoencephalitis from other viral central nervous system infections

BACKGROUND

Hallmarks of cytomegalovirus (CMV) meningoencephalitis include fever, altered mental status, or meningismus with pleocytosis, elevated protein and hypoglycorrhachia on cerebrospinal fluid (CSF) analysis. Magnetic resonance imaging may show ventriculitis, ependymitis or periventricular enhancement. Studies are limited comparing clinical and laboratory characteristics to other viral etiologies.

OBJECTIVES

This multi-center, retrospective cohort analysis reviewed patients with CMV meningitis or encephalitis and compared clinical features, laboratory findings and outcomes to the most common viral causes of meningoencephalitis.

STUDY DESIGN

Patients with encephalitis or aseptic meningitis and detectable genetic material by polymerase chain reaction were identified. Clinical characteristics, laboratory findings and neuroimaging were collected from the electronic medical record. Data analysis was performed comparing CMV to other viral etiologies.

RESULTS

485 patients were evaluated and included cases of CMV (n = 36) which were compared with herpes simplex virus (n = 114), enterovirus (n = 207), varicella zoster virus (n = 41) and West Nile virus (n = 81). Human immunodeficiency virus (HIV) infection was seen more frequently in CMV infection compared with all other viral etiologies. Clinical presentations and CSF findings of other viral etiologies differ compared with CMV. Hypoglycorrhacia occurred more often with CMV compared with other viral pathogens. Outcomes were significantly worse compared with enterovirus, herpes simplex virus and varicella zoster virus but not West Nile virus.

CONCLUSIONS

CMV meningoencephalitis occurs most often in patients with HIV and encephalitis occurs more frequently than meningitis. Clinical and laboratory findings differ compared with other viral etiologies and can support consideration of CMV in the differential diagnosis of patients with meningoencephalitis.

Viral and Prion Infections Associated with Central Nervous System Syndromes in Brazil

Virus-induced infections of the central nervous system (CNS) are among the most serious problems in public health and can be associated with high rates of morbidity and mortality, mainly in low- and middle-income countries, where these manifestations have been neglected. Typically, herpes simplex virus 1 and 2, varicella-zoster, and enterovirus are responsible for a high number of cases in immunocompetent hosts, whereas other herpesviruses (for example, cytomegalovirus) are the most common in immunocompromised individuals. Arboviruses have also been associated with outbreaks with a high burden of neurological disorders, such as the Zika virus epidemic in Brazil. There is a current lack of understanding in Brazil about the most common viruses involved in CNS infections. In this review, we briefly summarize the most recent studies and findings associated with the CNS, in addition to epidemiological data that provide extensive information on the circulation and diversity of the most common neuro-invasive viruses in Brazil. We also highlight important aspects of the prion-associated diseases. This review provides readers with better knowledge of virus-associated CNS infections. A deeper understanding of these infections will support the improvement of the current surveillance strategies to allow the timely monitoring of the emergence/re-emergence of neurotropic viruses.

Infectious disease-associated encephalopathies

Infectious diseases may affect brain function and cause encephalopathy even when the pathogen does not directly infect the central nervous system, known as infectious disease-associated encephalopathy. The systemic inflammatory process may result in neuroinflammation, with glial cell activation and increased levels of cytokines, reduced neurotrophic factors, blood-brain barrier dysfunction, neurotransmitter metabolism imbalances, and neurotoxicity, and behavioral and cognitive impairments often occur in the late course. Even though infectious disease-associated encephalopathies may cause devastating neurologic and cognitive deficits, the concept of infectious disease-associated encephalopathies is still under-investigated; knowledge of the underlying mechanisms, which may be distinct from those of encephalopathies of non-infectious cause, is still limited. In this review, we focus on the pathophysiology of encephalopathies associated with peripheral (sepsis, malaria, influenza, and COVID-19), emerging therapeutic strategies, and the role of neuroinflammation.

Encephalopathy Associated with Severe Cytomegalovirus Infection in an Immunocompetent Young Woman

Primary cytomegalovirus (CMV) infection in healthy young adults is usually an asymptomatic or mononucleosis-like syndrome, whereas in immunocompromised patients, CMV can cause significant disease. In this study, we report an unusual case of primary CMV infection wherein the patient, an immunocompetent 21-year-old woman, presented severe encephalopathy, acute hepatitis, retinitis, and reactivation of latent Epstein-Barr virus. She developed confusion, high fever, headache, and tonic-clonic seizures. Brain magnetic resonance imaging showed high-intensity lesions in the medial temporal lobe and basal ganglia. Liver dysfunction was observed, and abdominal computed tomography revealed splenohepatomegaly. After fundus findings, the patient was diagnosed with CMV retinitis. Upon admission, she was treated with intravenous acyclovir and steroid pulse therapy. Considering both her serious clinical condition and elevated serum levels of interleukin-6, we speculated that her condition was similar to cytokine-storm-induced encephalopathy. On day 2 after admission, she showed prompt recovery from these clinical manifestations. Since blood CMV pp65 antigenemia was found to be positive, we administered ganciclovir for 2 weeks. On the basis of her clinical manifestations and the presence of blood CMV DNA and CMV pp65 antigenemia along with IgM kinetics, we finally diagnosed this patient with severe primary CMV infection. She left our hospital without sequelae 20 days after admission. The incidence of severe CMV disease in immunocompetent young adults might be higher than previously recognized. Noninvasive testing for CMV (such as CMV pp65 antigenemia and CMV DNAemia) is widely available and can help early diagnosis. Short-term glucocorticoid therapy might be beneficial in the treatment of encephalopathy in the early stages of primary CMV infection. Considering such a background, clinicians should keep severe primary CMV infection in mind as a differential diagnosis in the clinical setting.

Assessment of the FilmArray ME panel in 4199 consecutively tested cerebrospinal fluid samples

OBJECTIVES

In central nervous system infections, early and correct management is of utmost importance. Rapid syndromic panel testing can potentially provide valuable guidance. The FilmArray meningitis/encephalitis (ME) panel detects 14 pathogens through multiplex PCR. Our study objectives were to assess its performance compared with established diagnostic procedures, especially real-time quantitative PCR for detection of viruses, and to determine the diagnostic and clinical significance of discrepant results.

METHODS

All cerebrospinal fluid samples sent for viral diagnostics to our microbiological laboratory over 34 months were analysed with the ME panel and in-house real-time PCR for herpes simplex virus type 1 (HSV-1), HSV-2, varicella zoster virus and enteroviruses. Other pathogens detected by the panel were confirmed by routine diagnostic procedures. Discrepant results were analysed through interpretation of biological and clinical data, and performance data were calculated for individual pathogens.

RESULTS

Altogether, 315 pathogens were detected by the ME panel in 4199 cerebrospinal fluid samples (7.5%) and an additional 21 viral targets were identified using real-time PCR. Thirty-four ME panel detections were not confirmed, totalling 55 discrepant results. After discrepancy analysis, 20 false-positive and 21 false-negative ME panel results remained. Performance varied between pathogens. Sensitivity for HSV-1 was calculated at 82.4% (59.0%-93.8%) with three false-negative results. Also noteworthy were 13 false-negative enterovirus and eight false-positive Streptococcus pneumoniae results.

CONCLUSIONS

Our analysis shows good performance for the ME panel in diagnosing central nervous system infection. The risk of false-negative HSV-1 results, however, warrants additional testing when encephalitis is suspected. Uncertainties in interpretation of enterovirus and S. pneumoniae results represent other limitations.

Disorders of the Cauda Equina

PURPOSE OF REVIEW

Cauda equina dysfunction (often referred to as cauda equina syndrome) is caused by a diverse group of disorders that affect the lumbosacral nerve roots. It is important to recognize dysfunction of the cauda equina quickly to minimize diagnostic delay and lasting neurologic symptoms. This article describes cauda equina anatomy and the clinical features, differential diagnosis, and management of cauda equina disorders.

RECENT FINDINGS

The diagnosis of disorders of the cauda equina continues to be a challenge. If a compressive etiology is seen, urgent neurosurgical intervention is recommended. However, many people with clinical features of cauda equina dysfunction will have negative diagnostic studies. If the MRI is negative, it is important to understand the diagnostic evaluation and differential diagnosis so that less common etiologies are not missed.

SUMMARY

Cauda equina dysfunction most often occurs due to lumbosacral disk herniation. Nondiskogenic causes include vascular, infectious, inflammatory, traumatic, and neoplastic etiologies. Urgent evaluation and surgical intervention are recommended in most cases of compressive cauda equina syndrome. Other types of treatment may also be indicated depending on the etiology.

Targeting the Choroid Plexuses for Protein Drug Delivery

Delivery of therapeutic agents to the central nervous system is challenged by the barriers in place to regulate brain homeostasis. This is especially true for protein therapeutics. Targeting the barrier formed by the choroid plexuses at the interfaces of the systemic circulation and ventricular system may be a surrogate brain delivery strategy to circumvent the blood-brain barrier. Heterogenous cell populations located at the choroid plexuses provide diverse functions in regulating the exchange of material within the ventricular space. Receptor-mediated transcytosis may be a promising mechanism to deliver protein therapeutics across the tight junctions formed by choroid plexus epithelial cells. However, cerebrospinal fluid flow and other barriers formed by ependymal cells and perivascular spaces should also be considered for evaluation of protein therapeutic disposition. Various preclinical methods have been applied to delineate protein transport across the choroid plexuses, including imaging strategies, ventriculocisternal perfusions, and primary choroid plexus epithelial cell models. When used in combination with simultaneous measures of cerebrospinal fluid dynamics, they can yield important insight into pharmacokinetic properties within the brain. This review aims to provide an overview of the choroid plexuses and ventricular system to address their function as a barrier to pharmaceutical interventions and relevance for central nervous system drug delivery of protein therapeutics. Protein therapeutics targeting the ventricular system may provide new approaches in treating central nervous system diseases.

Donor CMV-specific cytotoxic T lymphocytes successfully treated drug-resistant cytomegalovirus encephalitis after allogeneic hematopoietic stem cell transplantation

Background: Cytomegalovirus (CMV) infection of the central nervous system (CNS) is a rare but life-threatening complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Cases presentation: Two patients with drug-resistant CMV encephalitis after allo-HSCT were successfully treated with donor CMV-specific cytotoxic T lymphocytes (CTLs). In the first case, a 27-year-old male who received haploidentical transplantation to treat T-cell acute lymphoblastic leukemia (T-ALL), developed CMV encephalitis during the time of the ganciclovir maintenance treatment. After intravenous foscarnet and donor CMV-specific CTLs, CMV-DNA of CSF became undetectable and the abnormal signs of brain magnetic resonance imaging (MRI) were limited. Another case, a 57-year-old female with acute myeloid leukemia (AML) who underwent haploidentical transplantation, also developed CMV encephalitis during the maintenance treatment of the ganciclovir. After administering donor CMV-specific CTLs intrathecally, the CMV load of the CSF decreased.Conclusions: The intravenous/intratheca administration of donor CMV-specific CTLs may be a safe and effective treatment for CMV encephalitis, especially for patients who suffered from drug-resistant CMV infection.

Involvement of heparan sulfate during mouse cytomegalovirus infection in murine-derived immortalized neuronal cell line

Cytomegalovirus infection cause of severe developmental disorders of the CNS. Aim: In this study, we utilized a differentiated mouse-derived hippocampal cell line (dHT22) to understand mouse CMV (MCMV) infection. Results: The expression of immediate early genes ( IE) 1 and 3 confirmed the time-dependent susceptibility of dHT22 cells to MCMV infection. MCMV infection alters the cellular distribution of heparan sulfate (HS). In addition, pretreatment with heparinase significantly reduces virus infectivity. Conclusion: The compartmentalization of HS in MCMV infected cells suggests multiple roles of HS in virus life cycle ranging from viral entry to viral transport and cellular remodeling. An enzymatic heparinase assay confirmed that HS is critical for viral entry and trafficking.

Inhibition of Human Cytomegalovirus Entry into Host Cells Through a Pleiotropic Small Molecule

Human cytomegalovirus (HCMV) infections are wide-spread among the general population with manifestations ranging from asymptomatic to severe developmental disabilities in newborns and life-threatening illnesses in individuals with a compromised immune system. Nearly all current drugs suffer from one or more limitations, which emphasizes the critical need to develop new approaches and new molecules. We reasoned that a ‘poly-pharmacy’ approach relying on simultaneous binding to multiple receptors involved in HCMV entry into host cells could pave the way to a more effective therapeutic outcome. This work presents the study of a synthetic, small molecule displaying pleiotropicity of interactions as a competitive antagonist of viral or cell surface receptors including heparan sulfate proteoglycans and heparan sulfate-binding proteins, which play important roles in HCMV entry and spread. Sulfated pentagalloylglucoside (SPGG), a functional mimetic of heparan sulfate, inhibits HCMV entry into human foreskin fibroblasts and neuroepithelioma cells with high potency. At the same time, SPGG exhibits no toxicity at levels as high as 50-fold more than its inhibition potency. Interestingly, cell-ELISA assays showed downregulation in HCMV immediate-early gene 1 and 2 (IE 1&2) expression in presence of SPGG further supporting inhibition of viral entry. Finally, HCMV foci were observed to decrease significantly in the presence of SPGG suggesting impact on viral spread too. Overall, this work offers the first evidence that pleiotropicity, such as demonstrated by SPGG, may offer a new poly-therapeutic approach toward effective inhibition of HCMV.

Educational Case: Opportunistic Infections of the Central Nervous System

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040.¹.

CMV Encephalitis/Radiculitis: The Difficulty in Diagnosing in an Intubated Patient

Cytomegalovirus (CMV) can cause severe disease including colitis, pneumonitis, and less commonly encephalitis, in profoundly immunocompromised individuals. CNS imaging findings are nonspecific and diagnosis is made by identifying CMV in cerebral spinal fluid through PCR testing or cell culture. Early initiation of antiviral therapy is key with an overall poor outcome. Here we present a patient with newly diagnosed AIDS and pneumocystis jiroveci pneumonia who was febrile and remained encephalopathic for the first 6 weeks of his admission despite treatment and extensive work up for encephalopathy. Ultimately, he was diagnosed with CMV encephalitis and radiculitis and failed to improve significantly. This case is important because of multiple points (1) the uncommon presentation of CMV encephalitis/radiculitis occurring over 1 month into a hospitalization; (2) in the era of highly active antiretroviral therapy (HAART) severe complications of AIDS are rarely seen by newer generations of physicians and are not typically thought of; (3) the difficulties in evaluating altered mental status and weakness in an intubated patient receiving sedation. In immunosuppressed patients on mechanical ventilation, early evaluation with LP should be considered when altered mental status and fever of unclear etiology are present.

Mononeuritis multiplex: an uncommon neurological manifestation of cytomegalovirus reactivation in an HIV-infected patient

Background

Cytomegalovirus (CMV) reactivation with neurological involvement in patients with acquired immunodeficiency syndrome (AIDS) is increasingly rare since the introduction of antiretroviral therapy (ART). Manifestations include encephalitis, myelitis, polyradiculopathy and, less commonly, mononeuritis multiplex (MNM). We report a case of disseminated CMV disease with gastrointestinal and peripheral and central nervous system involvement in a patient with AIDS, manifesting primarily as MNM.

Case presentation

A 31-year old woman with AIDS presented with a clinical picture of MNM. Electromyography confirmed the clinical findings. CMV DNA was detected in cerebrospinal fluid (CSF) and blood. Gastrointestinal involvement was histologically documented. HIV RNA was also detected in CSF and brain MRI was consistent with HIV encephalopathy. A diagnosis of disseminated CMV disease (with esophagitis, colitis, encephalitis and MNM) and HIV encephalopathy was made. Treatment consisted of ganciclovir and foscarnet, followed by maintenance therapy with valganciclovir. Evolution was favorable and valganciclovir was stopped after sustained immune recovery following ART initiation.

Conclusion

We discuss the diagnostic approach to CMV neurological disease, with a focus on MNM and CMV encephalitis. Combination therapy with ganciclovir and foscarnet should be considered for all forms of neurological involvement, although available data are scarce. Since there is significant overlap between CMV encephalitis and HIV encephalopathy, ART drugs with higher CSF penetration may have to be considered. ART and immune recovery are essential to improve outcomes.

HIV and spinal cord disease

The epidemiology of spinal cord disease in human immunodeficiency virus (HIV) infection is largely unknown due to a paucity of data since combination antiretroviral therapy (cART). HIV mediates spinal cord injury indirectly, by immune modulation, degeneration, or associated infections and neoplasms. The pathologies vary and range from cytotoxic necrosis to demyelination and vasculitis. Control of HIV determines the differential for all neurologic presentations in infected individuals. Primary HIV-associated acute transverse myelitis, an acute inflammatory condition with pathologic similarities to HIV encephalitis, arises in early infection and at seroconversion. In contrast, HIV vacuolar myelopathy and opportunistic infections predominate in uncontrolled disease. There is systemic immune dysregulation as early as primary infection due to initial depletion of gut-associated lymphoid tissue CD4 cells and allowance of microbial translocation across the gut that never fully recovers throughout the course of HIV infection, regardless of how well controlled. The subsequent proinflammatory state may contribute to spinal cord diseases observed even after cART initiation. This chapter will highlight an array of spinal cord pathologies classified by stage of HIV infection and immune status.

Potential Pathways for CNS Drug Delivery Across the Blood-Cerebrospinal Fluid Barrier

The blood-brain interfaces restrict the cerebral bioavailability of pharmacological compounds. Various drug delivery strategies have been developed to improve drug penetration into the brain. Most strategies target the microvascular endothelium forming the blood-brain barrier proper. Targeting the blood-cerebrospinal fluid (CSF) barrier formed by the epithelium of the choroid plexuses in addition to the blood-brain barrier may offer added-value for the treatment of central nervous system diseases. For instance, targeting the CSF spaces, adjacent tissue, or the choroid plexuses themselves is of interest for the treatment of neuroinflammatory and infectious diseases, cerebral amyloid angiopathy, selected brain tumors, hydrocephalus or neurohumoral dysregulation. Selected CSF-borne materials seem to reach deep cerebral structures by mechanisms that need to be understood in the context of chronic CSF delivery. Drug delivery through both barriers can reduce CSF sink action towards parenchymal drugs. Finally, targeting the choroid plexus-CSF system can be especially relevant in the context of neonatal and pediatric diseases of the central nervous system. Transcytosis appears the most promising mechanism to target in order to improve drug delivery through brain barriers. The choroid plexus epithelium displays strong vesicular trafficking and secretory activities that deserve to be explored in the context of cerebral drug delivery. Folate transport and exosome release into the CSF, plasma protein transport, and various receptor-mediated endocytosis pathways may prove useful mechanisms to exploit for efficient drug delivery into the CSF. This calls for a clear evaluation of transcytosis mechanisms at the blood-CSF barrier, and a thorough evaluation of CSF drug delivery rates.

[Wernicke-Korsakoff syndrome secondary to cytomegalovirus encephalitis: A case report]

Cytomegalovirus (CMV) is one of the opportunistic microorganisms with the highest prevalence in immunocompromised patients. Reactivation has decreased after the introduction of highly active antiretroviral therapy (HAART). Encephalitis has been reported in the coinfection as one of the most frequent presentations.We present the case of a young adult patient with HIV infection and rapid neurological deterioration due to classic clinical symptoms and signs of the Wernicke-Korsakoff syndrome, with no risk factors for thiamine deficiency, with images by nuclear magnetic resonance typical of the syndrome, and identification of cytomegalovirus in cerebrospinal fluid. The specific treatment for CMV managed to control the symptoms with neurological sequelae in progression towards improvement.This is one of the few cases reported in the literature of Wernicke syndrome secondary to cytomegalovirus encephalitis.

Frequent occurrence of therapeutically reversible CMV-associated encephalopathy during radiotherapy of the brain

BACKGROUND

Neurological decline during radio(chemo)therapy of the brain is often attributed to disease progression or side effects of radiotherapy. Diagnosis of opportunistic neurotropic infections such as cytomegalovirus (CMV) infections is uncommon, even though high-grade gliomas and some brain metastases are known to contain CMV particles. We prospectively examined the frequency of CMV encephalopathy during radiotherapy of the brain.

METHODS

Fifty patients requiring whole-brain radiotherapy for brain metastases (n = 27) or local radio(chemo)therapy of the brain for high-grade gliomas (n = 23) were observed in the prospective observational GLIO-CMV-01 study. MRIs and blood samples were obtained before, halfway through, and at the end of radiotherapy. MRIs were screened for disease progression or increased intracranial pressure. Blood was tested for anti-CMV immunoglobulin (Ig)M, anti-CMV IgG, and CMV DNA.

RESULTS

Thirty-two of 50 (64%) patients were positive for anti-CMV IgG before radio(chemo)therapy. Fifteen of those 32 (48%) developed viremia during or up to 28 days after treatment. Thirteen of those 15 (87%) required treatment for CMV-associated encephalopathy. MRIs were negative for disease progression, edema, or bleeding. None of the patients negative for anti-CMV IgG developed viremia, suggesting a reactivation rather than a primary infection.In the group at risk consisting of anti-CMV IgG+ patients, age >65 (P = .004) and the amount of dexamethasone taken during radio(chemo)therapy (P = .004) were associated with an increased risk for CMV-associated encephalopathy. One hundred and fifty days after the start of radio(chemo)therapy, survival was 74% (14/19) (no encephalopathy) versus 54% (7/13) (encephalopathy) (odds ratio, 0.42; 95% CI, 0.03-1.86; P = .25).

CONCLUSION

CMV reactivation frequently causes encephalopathy during radio(chemo)therapy of the brain. The unexpected high incidence of this infection makes it highly clinically relevant for every treating physician.

Polyradiculopathy and Gastroparesis due to Cytomegalovirus Infection in AIDS: A Case Report and Review of Literature

Patient: Female, 46

Final Diagnosis: CMV gastroparesis and radiculopathy

Symptoms: Nausea • paraplegia • urinary retention • vomiting

Medication: —

Clinical Procedure: Lumbar puncture

Specialty: Infectious Diseases

In vitro drug combination studies of Letermovir (AIC246, MK-8228) with approved anti-human cytomegalovirus (HCMV) and anti-HIV compounds in inhibition of HCMV and HIV replication

Despite modern prevention and treatment strategies, human cytomegalovirus (HCMV) remains a common opportunistic pathogen associated with serious morbidity and mortality in immunocompromised individuals, such as transplant recipients and AIDS patients. All drugs currently licensed for the treatment of HCMV infection target the viral DNA polymerase and are associated with severe toxicity issues and the emergence of drug resistance. Letermovir (AIC246, MK-8228) is a new anti-HCMV agent in clinical development that acts via a novel mode of action and has demonstrated anti-HCMV activity in vitro and in vivo. For the future, drug combination therapies, including letermovir, might be indicated under special medical conditions, such as the emergence of multidrug-resistant virus strains in transplant recipients or in HCMV-HIV-coinfected patients. Accordingly, knowledge of the compatibility of letermovir with other HCMV or HIV antivirals is of medical importance. Here, we evaluated the inhibition of HCMV replication by letermovir in combination with all currently approved HCMV antivirals using cell culture checkerboard assays. In addition, the effects of letermovir on the antiviral activities of selected HIV drugs, and vice versa, were analyzed. Using two different mathematical techniques to analyze the experimental data, (i) additive effects were observed for the combination of letermovir with anti-HCMV drugs and (ii) no interaction was found between letermovir and anti-HIV drugs. Since none of the tested drug combinations significantly antagonized letermovir efficacy (or vice versa), our findings suggest that letermovir may offer the potential for combination therapy with the tested HCMV and HIV drugs.

Criteria for reducing unnecessary testing for herpes simplex virus, varicella-zoster virus, cytomegalovirus, and enterovirus in cerebrospinal fluid samples from adults

Excessive utilization of laboratory diagnostic testing leads to increased health care costs. We evaluated criteria to reduce unnecessary nucleic acid amplification testing (NAAT) for viral pathogens in cerebrospinal fluid (CSF) samples from adults. This is a single-center split retrospective observational study with a screening cohort from 2008 to 2012 and a validation cohort from 2013. Adults with available results for herpes simplex virus 1/2 (HSV-1/2), varicella-zoster virus (VZV), cytomegalovirus (CMV), or enterovirus (EV) NAAT with CSF samples between 2008 and 2013 were included (n = 10,917). During this study, 1.3% (n = 140) of viral NAAT studies yielded positive results. The acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent subjects would have reduced HSV-1/2, VZV, CMV, and EV testing by 63%, 50%, 44%, and 51%, respectively, from 2008 to 2012. When these criteria were applied to the 2013 validation data set, 54% of HSV-1/2, 57% of VZV, 35% of CMV, and 56% of EV tests would have been cancelled. No clinically significant positive tests would have been cancelled in 2013 with this approach. The introduction of a computerized order entry set was associated with increased test requests, suggesting that computerized order sets may contribute to unnecessary testing. Acceptance criteria of >10 nucleated cells/μl in the CSF of immunocompetent adults for viral CSF NAAT assays would increase clinical specificity and preserve sensitivity, resulting in significant cost savings. Implementation of these acceptance criteria led to a 46% reduction in testing during a limited follow-up period.

Nervous System Complications of Systemic Viral Infections

Invasion of the central nervous system (CNS) by viral agents typically produces a meningoencephalitis in which either meningitis or encephalitis may predominate. Viruses may also infect cranial or spinal blood vessels to produce ischemic injury. Viral and other infections may also elicit a host immune response which is cross-reactive with components of the neural tissue, resulting in encephalomyelitis, transverse myelitis, injury to peripheral nerves, or optic neuritis. This chapter discusses the pathogenesis of CNS viral infections and reviews clinical features of these disorders, major agents responsible in immunocompromised and immunocompetent individuals, and treatment. Prion diseases and postinfectious viral CNS syndromes including postinfectious encephalomyelitis, acute hemorrhagic leukoencephalitis, cerebellar ataxia, and transverse myelitis are also discussed.

Unravelling the Gordian knot: diagnostic dilemma in an HIV-positive patient with neurological involvement

We report a case of a 40-year-old seropositive-HIV patient with a CD4 count of 120 who presented with fever, severe headache and neck stiffness. Suspecting a case of tubercular meningitis (TBM; as tuberculosis is the commonest opportunistic infection in HIV/AIDS patients in India), a lumbar puncture was performed and a cerebrospinal fluid study revealed TBM. The patient was started on combination antitubercular drug therapy from directly observed treatment, short course (DOTS) (Cat 1 regimen) along with pyridoxine 40 mg/day and adjunctive corticosteroid therapy. However, despite adequate antitubercular therapy for 4 weeks, the patient did not show any improvement in his clinical condition. On the contrary, in the process he developed cytomegalovirus (CMV) retinitis. So we question our learned readers if the coinfection of Mycobacterium tuberculosis and CMV should be implicated for the failure to respond to isolated antitubercular therapy contrary to our expectation.

Pathologic basis of central nervous system infections

Radiology provides valuable gross pathologic information about central nervous system (CNS) infections. Major categories of infectious lesions of the brain and spinal cord are recognized by imaging such as diffuse, focal, or multifocal. This article discusses the pathologic basis of these radiographic findings. It illustrates examples with gross and microscopic photographs of CNS infections, and the tissue reactions to these infections. Where the organism can spread within the CNS, and cellular responses to the organism underlie both the radiographic and pathologic findings.